Mediated Growth of Carbon Nitride Films via Spray‐Coated Seeding Layers for Photoelectrochemical Applications

Abstract

Polymeric carbon nitride (CN) has emerged as a promising semiconductor in photoelectrochemical devices, thanks to its unique electronic and catalytic properties, low price, stability in various chemical environments, and benign nature. Decent progress in the deposition and growth of CN layers on substrates has been achieved using several deposition and growth methods; however, the properties of the layer, including the quality of its contact with the substrate and its structural properties, are still largely dependent on the surface properties of said substrate. Here, a new approach is introduced in which a spray‐coated seeding layer composed of CN monomers directs the growth of a homogenous, thick CN layer on a substrate by calcination at high temperature in the presence of melamine vapor. Uniform CN layers with strong adhesion to the substrate are obtained. The influence of the seeding layer and the vapor composition on the photoelectrochemical, optical, and structural properties is studied in detail. The best‐performing electrode, based on urea as the seeding layer, demonstrates good activity as a photoanode in photoelectrochemical cells, reaching up to 300 µA cm−2 in the presence of a hole scavenger.

Recent Progress on Photoelectrochemical Water Splitting of Graphitic Carbon Nitride (g−CN) Electrodes

“…A similar approach was used for the fabrication of g−CN-based films on conductive carbon paper [ 67 ]. Recently, Shalom et al [ 68 ] developed a new approach to growing thick g−CN layer films via a spray-coated seeding layer composed of CN monomers, leading to an impressive photocurrent density of 300 μA cm −2 at 1.23 V versus RHE in the presence of a hole scavenger ( Figure 7 b), implying the high scalability potential of this method for the flexible material and device applications.…”

“…[ 66 ] Copyright 2018 John Wiley and Sons Ltd. ( b ) Digital photo of the spray coater system, Reprinted with permission from ref. [ 68 ] Copyright 2021 Wiley-Blackwell. ( c ) A diagram illustrating the process of electrophoretic deposition, digital image of the deposited g−CN on FTO glass, carbon paper, and nickel foam, Reprinted with permission from ref.…”

Modulation of photogenerated holes for enhanced photoelectrocatalytic performance

“…The consumption of holes can ensure that the subsequent holes continue to migrate and improve the PEC efficiency. Commonly used sacrificial agents in PEC systems include Na 2 S-Na 2 SO 3 [20,21] , triethanolamine (TEOA) [22,23] and H 2 O 2 [24][25][26] and these have been widely used to evaluate interfacial charge transfer properties. Thorne et al measured the photocurrent-voltage curves of a hematite photoanode and found that the photoanode with H 2 O 2 as hole scavengers has lower onset potential values [24] .…”

Photocatalyst-Incorporated Cross-Linked Porous Polymer Networks

“…), polymeric carbon nitride stands out, since it represents a family of materials . Hence, by rational design approach, it is possible to tune many parameters such as conductivity, charge separation, crystallinity, porosity, absorption, dispersibility, and sheet size. − Some of the most popularized photoredox-based applications of semiconductors include water splitting, − organic synthesis, , photovoltaics, , environmental remediation, CO 2 photoreduction, polymer synthesis, − and photoelectrochemical transformations. , …”